1. Field of the Invention
The present invention relates to a photoresist residue removal composition, capable of removing residues caused by plasma etching and ashing of a metal or silicon oxide layer under a photoresist pattern in a semiconductor fabrication process. More specifically, the present invention relates to a photoresist residue removal composition, which essentially contains glycolic acid, and thus has a high capability to remove photoresist residues without causing corrosion and is eco-friendly.
2. Discussion of Related Art
In a series of semiconductor fabrication processes such as photolithography, dry etching or wet etching for forming metal interconnections or contact points, plasma ashing, etc., organic or metallic residues are generated. Thus, it is essential to first remove these undesired residues in order to carry out the subsequent processes.
Up to now, these residues have been removed under high temperatures between 60° C. and 85° C. using a composition containing hydroxylamine, alcohol amines, water, and a corrosion inhibitor. However, the composition including these amines generates hydroxyl ions in a water cleaning process, so that isopropyl alcohol (IPA) is used as an intermediate rinse in order to prevent corrosion.
Typical products used up to now include ACT-935 available from ACT Chemical Technology Co., Ltd. and EKC-265 available from E. I. du Pont de Nemours and Company. However, these compositions are generally limited in their applicability due to galvanic corrosion and toxicity.
With development of cleaning equipment and miniaturization of a semiconductor line width, new compositions using fluorine have currently been released in the market. These compositions add a polar solvent and a corrosion inhibitor to dilute hydrofluoric acid (DHF) or buffered oxide etchant (BOE) (i.e. a mixture of hydrofluoric acid (HF) with ammonium fluoride (NH4F)) used in an existing semiconductor fabrication process, and are used at room temperature (ranging from 20° C. to 30° C.). These compositions have an advantage in that no intermediate rinse is required, but a disadvantage in that control over the oxide attack of a pattern is required.
The photoresist residue removal compositions used up to now frequently cause damage to metal interconnections due to corrosive or galvanic reaction of a lower layer, and thus have a tremendous influence on an electric resistance value. Further, the photoresist residue removal compositions reduce a semiconductor device yield due to the influence of particles attached again to the surface of a wafer.
Further, the oxidant that is in use now, hydroxylamine, has very strong toxicity, and is always exposed to a possibility of product supply disruption due to the danger of explosion when formed.